Drafting implement



J. L. TANNER.

DRAFTING IMPLEMENT.

APPLICATION FILED SEPT.28, 1920.

1,402,269. t t d Jan. 3, 1922,

ml \1 lLUIE umrao STATES ears J' OHN L. TANNEB, OF DALLAS, TEXAS.

Nr orraea.

DRAITING IMPLEMENT.

incense.

Specification of Letters Patent.

Patented Jan. 3, 11922.

To all whom it ma concern:

Be it known that I,\JOHN L. TANNER, a citizen of the United States,residin at Dallas, in the county of Dallas and tate of Texas, haveinvented certain new and useful Improvements in Drafting Imple- 1 ments,of which the following is a specification.

This invention relates to new and useful improvements in draftingimplements.

The invention has particularly to do with an implement for laying out,or plotting curves of different degrees and combining line 3-3 of 1n asingle implement the functions of a plurality of implements.

In carrying outthe invention I provide a flat plate or member in which aplurality of curved slots is provided. Each slot has two curvedlongitudinal edges, one of which gives an even degree curve and theother of which produces a curve of a certain scale'at a givenmeasurement. For instance the bot- .tom curves of the slot maysuccessively range from one degree; while the to i curves may range from0 30' to 12 30. his arrangement gives a 30 curve at the top of eachslot. This implement is particularl useful in plotting railroadalinement. l t is also proposed to make a portion at one end of eachslot tangent thereto and this is particularly useful in engineeringwork.

The implement may be provided also with scales and graduati'ons alongits margins, but these are not essential elements of the invention.

The invention will be more readily understood from a reading of thefollowing specificationv and by reference to the accompanying drawings,in which an example of the invention is shown, and wherein:

Fig. 1 is a plan view of an implement constructed in accordance with myinven tion,

Fig. 2 is an edge view of the same, and Fig. 3 is a cross sectionaldetail on the Fig. 1. In the drawings the numeral 10 designates a flatplate or member which may be made of any suitable material, such ascelluloid composition. It is preferable to use a substantiallytransparent material, but this Y I plate having a plurality of slotsextending is not essential.

substantially longitudinal slots 11, each beginning at the left handmargin of the plate and curving downwardly at the right hand.

end. In Fig. 1 the lower edge 12 of the plate Is the bottom andthe upperedge 13 is the top3i The slots curve toward the bottom.

ach slot has two longitudinal edges or sldes 14 and 15, the bottom edgesbeing designated by 14 and the top edges by 15. At the left hand end ofeach slot a portion 11, tangentlal to the curve of the slot is provlded.

Designations are provided .at the left hand end of each slot indicatingthe degree of the curve represented by the lower edge 14 thereof. InFig. 1, I have shown thirteen slots and-the curves represented ran efrom one degree to thirteen degrees, but thls tion 11' registers withthe line of the drawing to which the curve-is to be added. Should thedesired curve be eight degrees, the plate is placed so that the portion11' of the slot having 8 degrees at its end will match along its loweredge with the line of the drawing. The lower edge 14 of the slot willgive the desired curve and the draftsman has only to trace along thelower edge of the slot, which acts as a guide. The same procedure isemployed for tracing any other curve.

A scale 16 may be placed along the margin at the bottom of the plate andthe marginal portions 17 of the other three edges may be used for thegraduations of a protractor, or any other measurement or scale. It ispreferable to round the corners of the plate so that the plate when madein a small size may be more readily slipped into a coat pocket when usedin the field and will not catch on objects on the drafting table.

What I claim, is:

In a drafting implement, an elongated longitudinally thereof, said slotsbeing lontions indicating the degree of curvature of gitudinally curved,each slot having a pair the lower edges of said slots, said plate alsoof longitudinally curved edges, the edges of having designationsindicating the degree each slot having different degrees of curvaofcurvature of the upper edges of said slots. 10 ture. said plate beingprovided at the cor- In testimony whereof I affix my signature.responding ends of said slots with designa- JOHN L. TANNER.

